1. Field of the Invention
The invention relates to a fuel injection valve that can control the supply of fuel by the movement of a valve member relative to a valve body and to an internal combustion engine provided with such a fuel injection valve.
2. Description of Related Art
In cylinder direct injection type engines in which fuel is directly injected into a combustion chamber deposits (oxides, carbides, decomposition products and the like) inherent to the fuel injected from the fuel injection valve adhere to the injection hole and periphery thereof, thereby decreasing the amount of injected fuel, changing the spray shape, and degrading controllability of combustion.
Using the cavitation of fuel flowing from a sack portion of the fuel injection valve into the injection hole is one of the methods for eliminating the adhesion of deposits to the inner surface of the injection hole. The fuel from the sack portion is throttled in an injection hole inlet of a very small diameter and the fuel pressure rises and immediately thereafter instantaneously falls when the fuel flows into the injection hole. As a result, cavitation is generated. The deposits are prevented from adhering and the adhered deposits are stripped by the energy of shock waves created by the cavitation.
For example, Japanese Patent Application Publication No. 2009-264193 (JP-A-2009-264193) describes the feature of inhibiting the adhesion of deposits by cavitation in a fuel injection valve provided with an injection hole in the form of a flat circular sector-shaped slit nozzle. Further, JP-A-2009-264193 suggests reducing the surface roughness of that portion of the inner surface of the injection hole where cavitation is unlikely to occur or forming a film that inhibits the adhesion of deposits to this portion.
However, the technical features suggested in JP-A-2009-264193 make it difficult for the deposits to adhere, but do not remove the deposits.